The present invention relates to a system for optimizing the telecommunication of formatted data streams between a host computer, on the one hand, and a device that notes the data stream content in an addressable buffer, on the other. The device may be, for example, a screen-type display terminal, a printer, or other apparatus. The host and device may be in close physical proximity, as in the case of a local terminal at the site of the host, or they may be physically remote, as in the case of a dial-up terminal used to communicate with the host.